Destructive hydrogenation



Patented July s, 1952 DESTRUCTIVE HYDROGENATION Joseph B. McKinley and William C. Starnes, Pittsburgh, Pa., assignors to Gulf Research &

Development Company, Pittsburgh, Pa., a corporation of Delaware Application December 8, 1948, Serial No. 64,-185

9 claims. (c1. 19e-5a) This invention relates to improved destructive hydrogenation procedure. The destructive hydrogenation of loW grade carbonaceous materials such as refractory gas with hydrogen sulfide to at least partially convert the hydrogenating component of the catalyst into sulde. Water vapor is formed duringthis hydrogen sulde treatment but the partial pressure of the water vapor is prevented from rising to an extent which will cause material deactivation of the catalyst. The conversion to the suloil, coal tars, mineral oil tars, etc. in order to 5 de may be @Omplete 01' Partial but the ameunt convert them into products of higher value such of hydrogenating lmetal oxide left unsulded as gasoline, has been known for a considerable should be insuflicient to form a partial pressure period of time. The procedure generally involves of Water vapor which will cause a material deaccontacting the hydrocarbon material With a hY- tVatiOIl 0f the Catalyst When the Catalyst iS Iedrogenating catalyst and hydrogenat elevated Used in the destructive hydlegeneton DIOCeSS- pressure and temperature. "In recent times it In the following examples and deSCriDtiOn We has been known to employ a. combination catahave set forth several of the preferred embodilyst comprising hydrogenating and active'crackments of our invention butY it is to be understood ing components. It is common practice to pethat they are given `by Way of illustration and not riodically regenerate the catalyst to remove conl5 in limitation thereof. g taminating material deposited thereon such as `To illustrate the extent of deactivation by Steam carbon and tars. This is accomplished by terof a destructive hydrogenaton catalyst comprisminating the above-described operation when the ing a hydlgenating metal oxide andv an active catalyst activity decreases, depre'ssuring threcracking catalysty We have Carried Out a Series actor, iiushing the catalyst bed with ari inert of experiments with a catalyst containing nickel oxygen-free gas such as nitrogen to remove volamonoxide deposited on a synthetic silica-alumina tile hydrocarbons, and passing an oxygen-concracking catalyst, the nickel monoxide being 8.3 taining gas over the contact at elevated temper- Der Centv by Weight 0f the COIIIPOSte- This Cataature to remove the carbonaceous material by 1YSt Was prepared by impregnating a CO-Dleeipioxidation or combustion. It is common practice tated Silica-alumina Catalyst With a nickel nito pressure-up the reactor containing the retrate aqueous solution followed by drying and generated catalyst, after nitrogen flushing, at calcining. vSeparate portions of this catalyst were near the reaction temperature with hydrogen and treated with Varying Partial DITeSSUI'eS 0f Steam then to go on stream pumping the hydrocarat 800 F. and at an approximately constant parbon and hydrogen mixture over the catalyst. It tial pressure (1790-2085 p.s. i.) of hydrogen for has been found that the metal oxide of the hyone hour. Thesample of catalyst (30 grams) lto drogenating component of the catalyst reduces be treated was placed in a 1,875 ml. bomb which rapidly during these operations involving its rewas heated to treatment temperature and use, and particularly during the pressuring-up charged with suilicient Water and hydrogen to operation, to yield relatively high partial presgive the desired steam and hydrogen partial sures of steam. 1 pressures. A correction was made for the steam We have found that the high pressure steam which would be formed by the rapid reduction of which is formed by reduction of the hydrogenatthe nickel oxide under the treating conditions. ing metal oxide during its re-use in destructive At the end of the treating period the steam and -hydrogenation operations, results in a perma- 40 hydrogen were vented from the bomb which was nent deactivation of va catalyst of the type comthen thoroughly flushed with prepuriiied' nitroprising a hydrogenating component and an active gen and evacuated. The bomb was cooled and cracking carrier base. We have also found that the catalyst recovered from it was recalcined in this undesirable deactivation can be avoided by air at 900 Fjin a stan'cilardizedy manner and then treating such a catalyst after the regeneration used in the hydrocracking runs described in TableI to test its hydrocracking activity. The results and the manner of conducting the tests are given in Table I.

TABLE I Eect of steam partial pressure during steaming-reduction on the activity of an 8.3% N-91.7% synthetic silica-alumina catalyst 1 Run. No 1 2 4 5 Catalyst:

Pretreatment Given None 30 p. s. i. Steam 54 p. s. 1 Steam 110 p. s 1 Steam 175 p. s. 1. Steam +2085 p. s. i. Hz +2000 p s i. Hz +1955 p s i. Hz +1700 p. s. i. Hz. Surface Area, Mz/g 245.0 215.3 4.8. Productsv (Weight Per Cent of Cycle Stock):

Gasoline 4l.8.. 37,5. Gasoline and Gas 53.6 46.1. Hydrogen Consumption 2.08 1.78.

(Weight Per Cent of Cycle Stock).

1 Tests were made charging 175.0 g.

of light cycle stock froma catalytic cracking operation 13.6 g.

of catalyst, dried in air at 900 F. for approximately one hour immediately before use, and 8.5-8.7 g.

of hydrogen to an 187`5-m1. rocking bomb. Each run involved ,a set heating of, the bomb to reaction temperature (812 F.), a set heating period at this temperature. and a set cooling to room temperature.

The maximum reaction pressure was ca. 2000 p. s. i. in each run.

The catalyst was prepared by vacuum impregnating the synthetic silica-alu1nina crackingV catalyst:v precalcined overnight :1t

1000 F., with an aqueous nickel nitrate solution. for hours and calcined overnight at 900 F. was not determined.

Itis evident from the foregoing that a catalyst comprising a hydrogenating component deposited on a cracking base is undesirably affected as regards activity and surface area by high partial pressures of steam and especially by partial `pressures above about pounds p. s. i.

The inspection on the charge stock used in the above experiments is given in Table II.

' TABLE II Inspections of light cycle charye stock Sp. gr. at /60 F 0.8713 Viscosity, SUS at F 36.2 Sulfur, percent f.. 0.20 Refractive index, nD2 1.4938 Aniline'pt.; F 122.7 Bromine No 4.4 Molecular weight (average) 209 Composition (weight percent): t

' Naphthenes and parans 13.7 Olens 3.1 Aromatics 63.2 Distillation:

Y Weight percent to F. at 10 mm.

(Gasoline) 3.4 Weight percent above 180 F. at 10 mm. (gasoil) 96.6

Calculations were carried out to determine the partial pressures of steam Whichmay be developed when a typical destructive hydrogenation catalyst lof this type is pressured-up with hydrogen under conditions corresponding to those normally employed in commercial destructive. hydrogenation operations, i. e., a temperature of about 800'? F. and a hydrogen pressure of 2000 p. s. i. It was assumed that a' sample vof a catalyst comprising nickel monoxide or molybdenum trioxide, as the case may be, on a synthetic silica-alumina cracking'catalyst was exposed to the conditions mentionedabove and the amount of steam which could he formed by the ensuing reduction was calculated. The results are plotted in the accompanying drawing from Which it may be seen that partial pressures of steam greatly in excess of 30 pounds are formed when destructive hydrogenation catalyst of this type are exposed to hydrogen under conventional destructive hydrogenation conditions.

` The treatment with hydrogen sulde, in order to avoid the above-described harmful effects of water vapor, must be carriedout inv such a manner that the partial pressure of the Water vapor The impregnated base was then dried at 136 C. The surface area of the catalyst in runs 3 and -i formed during the -hydrogen sulde treatment does not rise suliciently high to cause material deactivation. In general the partial pressure of Water vapor formed during the hydrogen sulde treatment should be kept below approximately 30 pounds. The sulde treatment may be complete, i. e., all of the hydrogenating component may be convertedl into sulfide. However, this is not necessary andvin some cases it is benecial to only partially sulde. In any event the sulfiding should -be carried to a point such that harmful amounts of water vapor will not be formed when the catalystis used for destructive hydrogenation. In other words, sucient suliiding should take place so that the partial pressure of water vapor formedwill be below approximately 30 p. s. i. when the catalyst is re-used in the destructive hydrogenation process. Straight hydrogen suldemay be.v used or Imay be mixed with an inert diluent-such asnitrogen. The hydrogen sulfide or the mixture containing it can be merelypassed over or through the contact which should be at elevated temperature su'icient to cause rapid formation of the sulfide. The sulding can take place at atmospheric pressure or at elevated pressure. In some instances it is advantageous to start the treatment at atmospheric pressure and then to gradually increase the pressure. Control of the partial pressure of water vapor is conveniently accomplished by regulating the spacevelocity ofthe hydrogen sulfide gas or mixture passed over the catalyst, i. e., the higher the space velocities, the lower the partial pressure of water vapor. The same result is accomplished by regulating the amount of HzS-i. e., the smaller the amount of HzS in the gas mixture, flowing over the contact at a given space velocity, the lower will be the partial pressure of the water vapor. Ordinarily the hydrogen sulde treatment is applied immediately' after regeneration and lilushing so that added heat is not required, the catalyst being at a high temperatureimmediately after the termination of the regeneration and flushing procedure. Sulding takes place rapidly and this is one of the advantages of the invention.

The degree of sulflding necessary for a catalyst will depend upon theamount of hydrogenating component on the catalyst, the ease of its reaction with hydrogen to give steam after partial sulding, the temperature of the subsequent hydrogen repressuring and destructive hydrogenation operations Whichwill effect the rate of steam formation, etc. It is possible to experimentally determine rate curves for sulding of various hydrogenating metals and to use this information to determine when the desired amount of suliiding has been accomplished in View of the exact method which is to'be employed in putting the reactor back on stream. Similar curves can be constructed from experimental data representing rates of reduction of -partially sulded contacts to form steam under-pressure, andit can thus be determined how fast reduction of a. catalyst will proceed during pressuring-up and subsequent destructive hydrogenation operations and to what extent pre-sulding must be carried so that the amount of water formed during the pressuring-up period will give a negligible steam partial pressure. Because ofthe many factors involved, as pointed out above, it is not possible to set forth pre-sulflding conditions which will give optimum results with every contact and every destructive hydrogenation process. However optimum conditions will usually be between about 0.25 and 4 hours, between about 600 and l000 F. and space velocities of between 500 and 2000 (gas measured at standard conditions).

In some destructive hydrogenation procedures, it is known to carry out the regeneration process at high pressures, about'the same as those used in the destructive hydrogenation, by using airliue gas mixtures for the combustion. The catalyst bed is flushed, after the regeneration, with nitrogen at reaction pressure and then the oil and hydrogen are owed together into the pressured reactor displacing the nitrogen. Our invention is also of value in connection with such a process.

For example, after displacing the air-flue gas I mixture with high-pressure nitrogen, high pressure nitrogen plus a small partial pressure of hydrogen suliide may be passed through the reactor until a desired degree of `suliiding of the catalyst has been obtained. Then the flow of hydrocarbon or the like and hydrogen through the lcatalyst bed may be started. The desired degree of suliiding is such that the partial pressure of the steam' formed in subsequent operations is low enough so as not to deactivate the catalyst.

Other similar applications, such as will be apparent to those skilled in the art, are possible.

The process of our invention is applicable in general to suliiding the hydrogenating component of a 'combined catalyst comprising said hyp drogenating component and an active cracking catalyst component and wherein the hydrogenating component is in the oxide form after the regeneration and is reduced to the metal or to a lower oxide form with concomitant formation of l water vapor when exposed to hydrogen under destructive hydrogenation conditions. Examples of such catalysts `are metals of the iron group, for instance nickel or cobalt, or metals of group VIa of the periodic system, such as molybdenum deposited upon active cracking catalysts such as co-precipitated silica-alumina catalysts, silicaalumina-zirconia cracking catalysts or silicaalumina cracking catalyts derived from natural sources such as calcined acid-treated naturallyoccurring montmorillonite.

As a specific example of the sulding method of protecting the activity of a hydrocracking catalyst, an 8.2 per cent NiO-91.8 per cent synthetic silica alumina catalyst was sulded by ilowing a 12.7 mol per cent hydrogen Smilde-87.3 mol rper cent nitrogen stream over it at a 575 space velocity for one hour at 900 F. at atmospheric pressure.

The term space velocity as used herein is the number of units of gaseous material, measured at 0 C. and 760 mm. of mercury, contacted with a unit volume of catalyst per hour. This sulfiding treatment has been found adequate to convert substantiallyv all of the NiO of the catalyst to NiS. The catalyst was ushed with nitrogen, cooled, and transferred to a continuous destructive hydrogenation apparatus. It filled twothirds of the catalyst case. The case was then pressured-up with 2000 p. s. i. of hydrogen at 900 F. for one hour. The following tabulation compares the activity of the catalyst so obtained with the activity of the same, but unsulded, catalyst subjected to the same hydrogen pressuring and. testing operation. Activities are judged by gasoline formation from light cycle stock (similar to that described in Table II) during a standardized destructive hydrogenation treatment.

Gasoline Formation During Hydrocracklng, Weight per cent of the Cycle Stock Catalyst Employed It is apparent that presulfiding protects the hydrocracking activity of the catalyst when it is pressured-up with hydrogen.

An alternative process is described in our coled application Serial No. 64,184, which comprises preliminary reduction with hydrogen at low pressure and then pressuring-up with hydrogen. This wouldavoid catalyst deactivation by high partial pressures of steam. It is sometimes advantageous to combine the hydrogenand hydrogen sulfide pretreatments. vThus presuliiding followed by prereduction can be used to eliminate or minimize the amount of hydrogen sulfide formed during pressuring-up and onstream operation. Treatment with hydrogen sulfide will convert the oxide to the sulde which would decompose during pressuring-up or onstream to give hydrogen sulfide which would contaminate the product. Following the sulding, treatment with hydrogen at low pressure will convert the sulde to the metal or a stable lower sulfide and the hydrogen sulde formed during the hydrogen treatment can be readily removed from the system. Simultaneous prereduction and presulding, using a mixture of hydrogen and hydrogen sulfide, can produce a catalyst which will not liberate hydrogen sulde during pressuring-up and during destructive hydrogenation.

What we claim is: l

l. In a process for the destructive hydrogenation. of a carbonaceousl material inthe presence of a reducible hydrogenating catalyst deposited upon an active cracking catalyst carrier, which combined catalyst is periodically regenerated to remove, by oxidation, carbonaceous material deposited thereon and the regenerated catalyst is re-used in the destructive hydrogenationv process, the improvement which comprises treating the regenerated catalyst with hydrogen sulfide to at least partially convert the oxidized hydrogenating component of the catalyst into sulide, preventing the partial pressure of water vapor formed during this treatment from rising to an amount which will cause material deactivation ofthe catalyst, and' continuing such treatment until the amount ofV hydrogenating component remaining 7 in the oxide form is insuiicient to form a partial pressure of Water vapor which will cause a material deactivation of the catalyst when the cat'- aiyst is re-used in the destructive hydrogenation process.

2. In a process for the destructive hydrogenation of a carbonaceous material in the presence of a reducible hydrogenating catalyst deposited upon an active cracking catalyst carrier, which combined catalyst is periodically regenerated to remove, by oxidation, carbonaceous material deposited thereon and the regenerated catalystis re-used in the destructive hydrogenation process, the improvement which comprises treating the regenerated catalyst with hydrogen sulfide to at least partially convert the oxidized hydrogenating component of the catalyst into sulfide, preventing the partial pressure of Water vapor formed during this treatment from rising to an amount which will cause material deactivation of the catalyst, and continuing such treatment until the amount of hydrogenating component remaining in oxide form will result in a partial pressure of water vapor of less than about 30 p. s. i. when the catalyst is re-used in the destructive hydrogenation process.

3. In a process for the destructive hydrogena-f tion of a carbonaceous material in the presence of a catalyst having cracking catalyst and reducible hydrogenating catalyst components, which combined catalyst is periodically regenerated to remove, by oxidation, carbonaceous material deposited thereon and the regenerated catalyst is re-used in the destructive hydrogenation process, the improvement which comprises treating the regenerated catalyst with hydrogen sulfide to at least partially convert the oxidized hydrogenating component of the catalyst into sulfide, maintaining the partial pressure of water vapor formed during this treatment below about 30 p. s; i. and continuing such treatment until the amount of hydrogenating component remaining in the oxide form will result in a partial pressure of water vapor of less than about 3o p. s.` i. when the catalyst is re-used in the destructive hydro,- genation process.

4. In a process for the destructive hydrogenation of a carbonaceous material in the presence of a catalyst having cracking catalyst and reducible hydrogenating catalyst components, which combined catalyst is periodically regenerated to remove, by oxidation, carbonaceous material deposited thereon and the regenerated catalyst is re-used in the destructive hydrogenation process, the improvement which comprises treating the regenerated catalyst with a mixture of hydrogen sulde and hydrogen to at least partially convert the oxidized hydrogenating component of the catalyst into sulfide and free metal, maintaining the partial pressure of water vapor formed during this treatment below about 30 p. s, i. and continuing such treatment until the amount of hydrogenating component remaining in thev oxide form will result in a partial pressure of Water vapor of less than about 30 p. s. i. when the catalyst is re-used in the destructive hydrogenation process.

5. In a process for the destructive hydrogenation of a carbonaceous material in the presence of a catalyst having cracking catalyst and reducible hydrogenating catalyst components, which combined catalyst is periodically regenerated to remove, by oxidation, carbonaceous material deposited thereon and the regenerated catalyst is re-used in the destructive hydrogenation process, the improvement which comprises treating the regenerated catalyst with hydrogen sulde to at least partially convert the oxidizedl hydrogenating component of the catalyst in the suliide, treating the sullded catalyst with hydrogen, maintaining the partial pressure of Water vapor formed during this treatment with hydrogen sulde and hydrogen below about 30 p. s. i. and continuing such treatment until the amount of hydrogenating component remaining in the oxide form Will-result in a partial pressure of water vapor of less than about 30 p. s. i. when the catalyst is re-used in the destructive hydrogenation process.

6. In a process for the destructive hydrogenation of a hydrocarbon in the presence of a catalyst having cracking catalyst and reducible hydrogenating catalyst components which combined catalyst is periodically regenerated to remove, by oxidation, carbonaceous material deposited thereon and the regenerated catalyst is re-used in the destructive hydrogenation process, the improvement which comprises treating the regenerated catalyst with hydrogen suliide to at least partially convert the oxidized hydrogenating component of the catalyst into sulfide, maintaining the partial pressure of water vapor formed during this treatment below about 30 p. s. i. and continuing such treatment until the amount of hydrogenating component remaining in the oxide form will result in a partial pressure of Water vapor of less than about 30 p. s. i. when the catalyst is re-used in the destructive hydrogenation process.

7. In a process for destructive hydrogenation of a hydrocarbon in the presence of a hydrogenating catalyst of the iron group of the periodic system deposited upon a silica-alumina cracking catalyst carrier which combined catalyst is periodically regenerated to remove, by oxidation, carbonaceous material deposited thereon and the regenerated catalyst is re-used in the destructive hydrogenation process, the improvement which comprises treating the regenerated catalyst with hydrogen sulde to at least partially convert the oxidized iron group component of the catalyst into sulde, maintaining the partial pressure of Water vapor formed during this treatment below about 30 p. s. i. and continuing such treatment until the amount of iron group metal oxide remaining in the catalyst will result in partial pressure of water vapor of less than about 30 p. s. i. when the catalyst is re-used in the destructive hydrogenation process.

8. In a process for destructive hydrogenation of a hydrocarbon in the presence of a hydrogenating catalyst selected from group VIa of the periodic system deposited upon a silica-alumina cracking catalyst carrier which combined cata.- lyst is periodically regenerated to remove, by oxidation, carbonaceous material deposited thereon and the regenerated catalyst is re-used in the destructive hydrogenation process, the improvement which comprises treating the regenerated catalyst with hydrogen sulfide to at least partially convert the oxidized group VIa component of the catalyst into sulfide, maintaining the partial pressure of water vapor formed during this treatment below about 30- p. s. i. and continuing such treatment until the amount of group VIa metal OXde remaining in the catalyst will result 1n a partial pressure of water vapor of less than about 30 p. s. i, when the catalyst is re-used in the destructive hydrogenation process.

9. In a process for the destructive hydrogena- 9 tion of a hydrocarbon in the presence of a nickel catalyst deposited upon an active cracking catalyst carrier which combined catalyst is periodically regenerated to remove, by oxidation, carbonaceous material deposited thereon and the regenerated catalyst is re-used in the destructive hydrogenation process, the improvement which comprises treating the regenerated catalyst with hydrogen sulfide to at least partially convert the nickel component of the catalyst into sulde,

maintaining the partial pressure of water vapor formed during this treatment below about 30 p. s. i. and continuing such treatment until the amount of nickel oxide remaining in the catalyst will result in a partial pressure of Water vapor of less' than about 30 p. s. i. when the catalyst is re-used in the destructive hydrogenation process.

JOSEPH B. MCKINLEY. WILLIAM C. STARNES.

REFERENCES CITED The following' references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,131,089 Beeck et al Sept. 27, 1938 2,232,909 Gohr Feb. 25, 1941 2,307,795 Kearby Jan. l2, 1943 2,334,159 Friedman Nov. 9, 1943 2,358,879 Redcay Sept. 26, 1944 2,369,009 Bloch et al Feb. 6, 1945 2,377,116 Voorhies et al May 29, 1945 2,386,050

Holder Oct. 2, 1945 

1. IN A PROCESS FOR THE DESTRUCTIVE HYDROGENATION OF A CARBONACEOUS MATERIAL IN THE PRESENCE OF A REDUCIBLE HYDROGENATING CATALYST DEPOSITED UPON AN ACTIVE CRACKING CATALYST CARRIER, WHICH COMBINED CATALYST IS PERIODICALLY REGENERATED TO REMOVE, BY OXIDATION, CARBONACEOUS MATERIAL DEPOSITED THEREON AND THE REGENERATED CATALYST IS RE-USED IN THE DESTRUCTIVE HYDROGENATION PROCESS, THE IMPROVEMENT WHICH COMPRISES TREATING THE REGENERATED CATALYST WITH HYDROGEN SULFIDE TO AT LEAST PARTIALLY CONVERT THE OXIDIZED HYDROGENATING COMPONENT OF THE CATALYST INTO SULFIDE, PREVENTING THE PARTIAL PRESSURE OF WATER VAPOR FORMED DURING THIS TREATMENT FROM RISING TO AN AMOUNT WHICH WILL CAUSE MATERIAL DEACTIVATION OF THE CATALYST, AND CONTINUING SUCH TREATMENT UNTIL THE AMOUNT OF HYDROGENATING COMPONENT REMAINING IN THE OXIDE FORM IS SUFFICIENT TO FORM A PARTIAL PRESSURE OF WATER VAPOR WHICH WILL CAUSE A MATERIAL DEACTIVATION OF THE CATALYST WHEN THE CATALYST IS RE-USED IN THE DESTRUCTIVE HYDROGENATION PROCESS. 